Vehicle emission control systems may be configured to store fuel vapors from fuel tank refueling and diurnal engine operations, and then purge the stored vapors during a subsequent engine operation. In an effort to meet stringent emissions regulations, emission control systems may need to be intermittently diagnosed for the presence of leaks that could release fuel vapors to the atmosphere.
However, different jurisdictions mandate different leak detection thresholds. For example, a subset of states in the United States (referred to as “green states” herein) mandate testing for leaks with a diameter of 0.02″ or greater, while other states mandate testing for leaks with a diameter of 0.04″ or greater. In contrast, European Union member countries do not require evaporative emissions leak testing. Further, the subset of green states is continually growing. In addition, new regulations are anticipated, such as testing for fuel tank leaks with a diameter of 0.01″ or greater in plug-in electric hybrid vehicles (PHEVs).
Compliance with differing evaporative emissions regulations results in challenges for automakers. Powertrain control modules (PCMs) must be calibrated according to the jurisdiction where the vehicle will be operated, increasing component complexity and/or part numbering complexity. Additionally, vehicles operated at or near the border of a green state and a non-green state are at a disadvantage for testing. A vehicle calibrated for green state testing thresholds may abide by overly strict regulations when operating in a non-green state. Similarly, a vehicle calibrated for non-green state testing thresholds may underdiagnose evaporative emissions leaks when operating in a green state.
The inventors herein have developed systems and methods to at least in part address the above issues. In one example, a method for detecting evaporative emissions system leaks, comprising: adjusting a leak detection threshold based on a vehicle geographical location including jurisdiction borders; and indicating a leak based on the adjusted threshold. In this way, a vehicle may perform OBD EVAP leak tests in accordance with local regulations. This method allows for a single PCM to be installed in all vehicles of a certain model during manufacturing regardless of the jurisdiction where the vehicle will be sold, thereby reducing part complexity and simplifying the manufacturing process.
In another example, a method, comprising: determining a vehicle's location via a global positioning system; determining an evaporative emissions leak detection threshold for the jurisdiction comprising the vehicle's location; and running an evaporative emissions leak test using the determined evaporative emissions leak detection threshold. In this way, a vehicle's PCM software does not require additional updates based on the vehicle's location. This method allows for vehicles traversing or updating registration across green state/non-green state borders to be compliant with local regulations without additional software updates.
In yet another example, a system for detecting evaporative emissions leaks in a vehicle, comprising: a global positioning system; an evaporative emissions testing subsystem configured to test for evaporative emissions leaks of at least two sizes; and a controller configured to: determine the vehicle's geographical location via the global positioning system; determine the evaporative emissions leak detection threshold for the jurisdiction comprising the vehicle's geographical location; and run an evaporative emissions leak test using the determined evaporative emissions leak detection threshold. In this way, unnecessary warranty service can be avoided in vehicles traversing green state/non-green state borders. The vehicle is not tied to the stricter green state regulations when running in non-green states.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.